The present invention relates to instruments for aiding in implanting prosthetic implants. More specifically, the present invention relates to an alignment guide to aid in seating a femoral knee implant.
In a typical knee replacement surgery, the end of the femur is prepared to receive a femoral knee implant by resecting bone in anterior, distal, posterior, and chamfer planes. In order to implant a constrained knee having a cam box additional bone must be removed to form a slot in the intercondylar region. After the femur is prepared the femoral implant is pressed onto the femur. As the implant is advanced onto the femur the anterior and posterior flanges of the implant contact the anterior and posterior surfaces of the femur before the cam box engages the slot in the femur. Because of this, the cam box may not be aligned with the slot. If the cam box and slot are not aligned, proper seating of the implant is impossible without repositioning the implant medially or laterally. Repositioning the implant can erode the carefully prepared bone surfaces and thereby compromise a precise fit between the implant and bone.